Heretofore, correlation coefficients have been employed to identify incoming pixel images such as radar return signals and character bit maps. The input pixel images were compared to-library template images on a pixel by pixel basis. The summation of all of the pixel comparisons in each image/template match produced a correlation coefficient indicating the closest match. However, these prior correlation techniques did not involve any change or enhancement of the pixels forming the library templates. U.S. Pat. No. 5,379,349, issued Jan. 3, 1995 to Hadar Avi-Itzhak (Ser. No. 07/937,732, filed Sep. 1, 1992 by the present assignee) entitled METHOD OF OCR TEMPLATE ENHANCEMENT BY PIXEL WEIGHTING; shows enhancement of library templates without provision for sub-classes of font versions.